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High Production of Maltooligosaccharides in the Starch Liquefaction Process: A Study on the Hyperthermophilic Mechanism of α-Amylase
Journal of Agricultural and Food Chemistry ( IF 5.7 ) Pub Date : 2023-03-23 , DOI: 10.1021/acs.jafc.3c00665 Min Liao 1 , Ruyue Dong 1 , Lanxue Li 1 , Xiaoqing Liu 2 , Yaru Wang 1 , Yingguo Bai 1 , Huiying Luo 1 , Bin Yao 1 , Huoqing Huang 1 , Tao Tu 1
Journal of Agricultural and Food Chemistry ( IF 5.7 ) Pub Date : 2023-03-23 , DOI: 10.1021/acs.jafc.3c00665 Min Liao 1 , Ruyue Dong 1 , Lanxue Li 1 , Xiaoqing Liu 2 , Yaru Wang 1 , Yingguo Bai 1 , Huiying Luo 1 , Bin Yao 1 , Huoqing Huang 1 , Tao Tu 1
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The efficient production of high-value-added bioproducts from starchy substances requires α-amylases with hyperthermophilic properties for industrial starch liquefaction. In this study, two hyperthermophilic α-amylases with significant differences in thermostability, PfAmy and TeAmy, were comparatively studied through structural analysis, domain swapping, and site-directed mutagenesis, finding that three residues, His152, Cys166, and His168, located in domain B were the main contributors to hyperthermostability. The effects of these three residues were strongly synergistic, causing the optimum temperature for the mutant K152H/A166C/E168H of TeAmy to shift to 95–100 °C and stabilize at 90 °C without Ca2+. Compared to PfAmy and TeAmy, the mutant K152H/A166C/E168H, respectively, exhibited 1.7- and 2.5-times higher starch hydrolysis activity at 105 °C and pH 5.5 (10411 ± 70 U/mg) and released 1.1- and 1.7-times more maltooligosaccharides from 1% starch. This work has interpreted the hyperthermophilic mechanism of α-amylase and thereby providing a potential candidate for the efficient industrial conversion of starch to bioproducts.
中文翻译：
淀粉液化过程中麦芽低聚糖的高产：α-淀粉酶超嗜热机制的研究
从淀粉物质中高效生产高附加值的生物产品需要具有超嗜热特性的 α-淀粉酶用于工业淀粉液化。本研究通过结构分析、结构域交换和定点诱变对两种热稳定性有显着差异的超嗜热α-淀粉酶Pf Amy和Te Amy进行了比较研究，发现其三个残基His152、Cys166和His168位于在域 B 中是超热稳定性的主要贡献者。这三个残基的作用具有很强的协同作用，导致Te Amy的突变体 K152H/A166C/E168H 的最适温度转移到 95–100 °C，并在没有 Ca 2+的情况下稳定在 90 °C 。与PF相比Amy 和Te Amy，即突变体 K152H/A166C/E168H，分别在 105 °C 和 pH 5.5 (10411 ± 70 U/mg) 下表现出高出 1.7 倍和 2.5 倍的淀粉水解活性，并且释放出高出 1.1 倍和 1.7 倍的淀粉来自 1% 淀粉的低聚麦芽糖。这项工作解释了 α-淀粉酶的超嗜热机制，从而为淀粉向生物产品的有效工业转化提供了潜在的候选者。
更新日期：2023-03-23
中文翻译：
淀粉液化过程中麦芽低聚糖的高产：α-淀粉酶超嗜热机制的研究
从淀粉物质中高效生产高附加值的生物产品需要具有超嗜热特性的 α-淀粉酶用于工业淀粉液化。本研究通过结构分析、结构域交换和定点诱变对两种热稳定性有显着差异的超嗜热α-淀粉酶Pf Amy和Te Amy进行了比较研究，发现其三个残基His152、Cys166和His168位于在域 B 中是超热稳定性的主要贡献者。这三个残基的作用具有很强的协同作用，导致Te Amy的突变体 K152H/A166C/E168H 的最适温度转移到 95–100 °C，并在没有 Ca 2+的情况下稳定在 90 °C 。与PF相比Amy 和Te Amy，即突变体 K152H/A166C/E168H，分别在 105 °C 和 pH 5.5 (10411 ± 70 U/mg) 下表现出高出 1.7 倍和 2.5 倍的淀粉水解活性，并且释放出高出 1.1 倍和 1.7 倍的淀粉来自 1% 淀粉的低聚麦芽糖。这项工作解释了 α-淀粉酶的超嗜热机制，从而为淀粉向生物产品的有效工业转化提供了潜在的候选者。
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